Dehumidifying device



May 9, 1950 H. A. LOCKWOOD DEHUMIDIFYING DEVICE Filed May 26, 1945 INVENTOR. flaw A. Lamruuaa s'qb' AGENT Patented May 9, 1950 Harry A. Lockwood, Merid'en, p onn as'signor, by mesne assignments, to NiIes-Bement-Pond' Company, West Hartford;

of New Jersey Corinl; a corporation Application May 26, 1945, serial No. 596,002;

The present invention relates to desiccating devices, and particularly to devices for preventing corrosion in a closed chamber by the removal of moisture from the air in said chamber.

The present invention is intended as an adaptation of the device shown in my copending application Serial No. 448,443. filed June 25, 1942, matured into Patent No. 2,407,023, issued September 3, 1946. This adaptation may function similarly to the'devic'e in my copen'ding application, but additional capabilities as described herein are provided.

Devices" of the type described in my copending application consist of generally cylindrical casings containing a quantity of desiccant. The casing is open only 'at one end. When such a device is used to dehydrate a closed chamber, its open end is' inserted in an opening in thewall of the chamber, so that the desiccating material in the casing can come into contact with the air in the chamber. When such devices are used, they are not always successful if the chamber to be dehydrated is large or irregularly shaped, or if there are other openings in the chamber, even though those other openings may be very small. For example, trouble has been encountered in the dehydration of radio instrument casings and apparatus where rotating control shafts pass thru the wall of the instrument casing. In such arrangements, variations in atmosphere pressure cause the instrument casing to breathe, allowing water vapor to enter the casing. If a desiccator plug having a blind end is used water vapor may enter the casing thru the other openings around the shafts, etc., faster than the desiccai tor plug can remove it.

The present invention is intended to overcome the difficulties encountered when the devices as shown in my previous application are used in instruments or devices of the types described. In the present device, it is proposed to open the casing at both ends so that air may pass thru it. It has been found that a desiccator open at both ends will not operate satisfactorily unless some means is provided to immobilize the desiccant particles. When the particles are free to change their relative position it has been found that the humidity of the air at the outlet end of the casing varies considerably, apparently due to a changing flow path thru the desiccant particles due to vibration. This inconsistency is overcome by spring means acting on the desiccant within the casing so as to maintain the particles immobilized.

An object of the present invention is to prosage of air therethru.

3' Claims; (ct-183 4.8)

2 vide a desiccatin'g device which may be placed in an aperture in the wall of aclosed chamber, and which is so constructed as to permit the cas sage of air thru the device into the chamber.

Another object of the present invention is 'to provide a desiccating device including granular desiccating material and spring means for maintaining the granular material immobilized.

A' further object of the invention is to provide a desicc'atorplug, which is open at both ends during use, but which may be effectively sealed for shipment and storage by providing a seal at one end only.

Other objects and advantages of the present invention will become apparent from a consider; ation of the appending specification, claims and drawing. v I v Thesinglefigure'of'the drawing shows, partly in elevation and partly in section, a desiccating device built in accordance with the principles of my invention. The drawing is intended only to clarify this description, not to limit specifically the characteristics of this device. The drawing shows an elongated, generally cylindrical casing H]. In the embodiment illustrated, the casing I0 is flanged at [2 and is provided with an external thread 54, to permit the fastening of the easing in an opening of appropriate size. The right end of the casing carries a perforated screen IS. A filter i8 is placed adjacent to perforated screen It to prevent the escape of particles of desiccant 29, which may be, for example, silica gel.

A seal 22 is provided at the right end of the casing It just outside the perforated screen I 6. The face on the seal 22 toward the casing I0 is spherical, so that it may engage the periphery of the casing It] at any of the various relative angular positions of the seal 22. The diameter of the seal 22 is such that it prevents use of the threads I4 until it is removed.

The other end of the casing I0 is closed by a cap member 24, which is bonded to the casing after filling with desiccant. The cap 24 is provided with a central aperture 25 which opens into the interior of the casing and permits the pas- It has been found that if the length of the passage 2t is approximately eight times its diameter, or longer, there will be no transmission of water vapor thru it unless a pressure differential, causing a positive airflow, occurs.

Therefore, it may be seen that when the seal 22 is in place, no water vapor passes into the interior of the casing ill, even though aperture 25 is open. Consequently, the plug can be shipped or stored for an appreciable length of time without depreciation of the desiccating material, providing the seal 22 is in place.

Inside the casing 10, a washer 28, provided with apertures 30 for air passage, is maintained in contact with the desiccant particles by a spring 32 which is retained by the cap 24. The spring 32 and the washer 28 cooperate to maintain the particles immobilized. The airflow paths between the particles are thereby made smaller and more tortuous, so that the air passing thru the casing as the seal is removed is forced to flow in more intimate contact with the desiccant particles. Furthermore, by maintaining the particles immobilized, the air is made to use consistently the same flow paths thru the particles.

It has been found, that with this arrangement, the humidity of the air at the outlet end of the plug increases slowly and consistently as saturation of the desiccant progresses.

While I have shown and described a, preferred embodiment of my invention, other modifications thereof will readily occur to those skilled in the art, and I therefore intend my invention to be limited only by the appended claims.

I claim as my invention:

1. A desiccating device comprising a generally cylindrical casing, granular desiccating material in said casing, breather openings through each end wall of said casing for permitting the flow :of air therethru, rigid detachable means for sealing the opening through one end wall of said casing, the opening through the other end wall comprising a straight passage approximately eight times as long as its diameter whereby there -is no appreciable flow of air into said casing thru 'said passage when said sealing means is in place. 2. A sealable container comprising a generally cylindrical casing, breather openings in each end of said casing for permitting the flow of air therethru, and rigid detachable means for sealing the opening at one end of said casing, the opening at the other endcomprising a straight passage not less than approximately eight times as long as its diameter whereby there will be no appreciable flow of air into said casing thru said passage when said sealing means is in place.

3. A desiccating device comprising a generally cylindrical casing, granular desiccating material in said casing, breather openings thru each end wall of said casing for permitting the flow of air therethru, rigid, detachable means for sealing the opening thru one end wall of said casing when said device is not in desiccating use; the opening thru the other end wall comprising a straight passage whose length in relation to its diameter is such that there is no appreciable flow of air into said casing when said sealing means is in place.

HARRY A. LOCKWOOD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PAR. E N IS Number Name Date 1,531,602 Folker Mar. 31, 1925 1,675,228 Schmidt June 26, 1928 1,759,971 Austin May 27, 1930 2,225,990 Henry Dec. 24, 1940 2,283,989 Henry May 26, 1942 2,315,049 Cronstedt Mar. 30, 1943 2,322,448 Johnson June 22, 1943 2,406,993 Chandler Sept. 3, 1946 2,407,023 Lockwood Sept. 3, 1946 

